Abstracts (first author)
Factors affecting juvenile movement in a house sparrow metapopulation – the role of time of birth and habitat configuration
Dispersal propensity may vary considerably between individuals in a population. Still, dispersal remains one of the least understood processes in ecology and evolution. In this study, we investigate individual variation in juvenile movement during the onset of the dispersal phase in four insular house sparrows Passer domesticus populations in northern Norway. The predictors were clutch size, hatch day, sex and morphology. The study islands differ in degree of patch isolation, configuration of suitable habitat, and characteristics of the matrix habitat. Thus, it was possible to assess the importance of such landscape features on movement. On one of the islands, movement rate was negatively related to hatch day. This pattern may be generated by age-dependent movement since early born individuals are older when the dispersal phase is initiated. However, we suggest that this relationship rather is a result of seasonal variation in the environment experienced by the nestlings, which affects their phenotype and propensity to disperse. Clutch size, sex, body size, mass and condition did not significantly explain variation in movement. On the other hand, movement rate seemed to decrease with increasing patch isolation, i.e. distance between patches and hostility of the matrix habitat. This suggests that habitat configuration is an important factor influencing movement and dispersal capacities of juvenile house sparrows.